Along with an increased demand for magnetic recording media with ever higher density recording, there is a demand for durability and storage stability under different environments.
Various investigations are underway for surface treatment of magnetic powders, made from ferromagnetic alloy powder, to impart stability to the magnetic powder surface and dispersibility to the magnetic powder, in order to obtain magnetic recording media having excellent electromagnetic characteristics, durability and storage stability. For example, phosphate compounds, silane coupling agents and so on have been used to surface-treated ferromagnetic alloy powders.
In recent years, there have been, in particular, proposals for using compounds containing triazine rings as surface treatment agents for ferromagnetic powders. See JP-A-61-96519 (the term "JP-A" as used herein refers to a "published unexamined Japanese patent application").
However, even with surface treatment by these triazine treatment agents, it has not been possible to obtain satisfactory dispersibility, running durability and storage stability in the case of those ferromagnetic alloy powders which are in the form of comparatively fine particles. It has been even more difficult to obtain the above properties when using ferromagnetic alloy fine powders which have an adsorbed amount of a C.sub.10 to C.sub.22 fatty acid of 5.times.10.sup.-6 mol/m.sup.2 or more. Such fatty acid-treated ferromagnetic alloy fine powders are particularly excellent in electromagnetic characteristics.